Diamidine of 2-hydroxystilbene



Patented May 30, 19 50 UNITED" STATES P 2,510,047

DIAIi/HDINE OF 1 2 HYDROXYSTI LBENE Arthur J ames Ewins, Leigh-on'xqSea,England; as

signor to May & Baker Limited, Dagenham,

Essex, England, aBritish company No. Drawing. OriginalapplicationDecemberfi, 1943",Serial'No. 512,779. Divided andtliisapplication February 25, 1948;.Serial No..10;940; InGreatBritain-NovemberA, 11941" Section 1, Public Law 690, August 8, 1946Patent expires November-4, 1961' 1 Claim. 1

This application is a divisional of patent application Serial No.512,779, now abandoned, and relatesto-a new diamidine derivative,Z-hydroxy- 4':l=*-diamidino-sti1bene,. and also-salts= thereof such asthe dihydrochloride.

The compound of this invention, as also are the saltsthereof', is usefulas atherapeutic possessing, as it does, a marked trypanocidal activity.As compared with the non-hydroxy substituted compound,4:4'-diamidino-stilbene, it exhibits a surprisingly greater therapeuticratio, an important advantage which could not have been foreseen. Theprimary product of this invention is prepared, for example, by treating2-hydroxy- 4:4-dicyano-stilbene in solution or suspension in ananhydrous alcohol (such as ethyl alcohol) with dry hydrogen chloride ordry hydrogen bromide, whereby the cyanogen groups are converted intoimino-ether hydrohalide groups and treating the compound so obtainedwith ammonia to yield the desired diamidine or a salt of the saiddiamidine. The alcoholic solution or suspension may contain an inertorganic diluent such as chloroform or nitrobenzene. In any case, wherenecessary, the end product is subjected to purification as byrecrystallisation.

The starting material, 2-hydroxy-4:4'-dicyano-stilbene, can be madefollowing methods known per se. Thus, for example, it can be preparedfrom the corresponding 2-nitro compound through2-amino-4:4'-dicyano-stilbene as hereinafter exemplified.

The invention may be illustrated by, but is not restricted to, thefollowing example:

EXAMPLE This example illustrates the preparation of2-hydroxy-4:4'-diamidino-stilbene from 2-hydroxyl:4-dicyano-stilbeneitself prepared from 2-nitro-4:4'-dicyano-stilbene through thecorresponding Z-amino compound.

2-m'tro-4:4'-dicycmostilbene 10 grams of 2-nitro-p-tolunitrile and 8.1grams of 4-cyano-benzaldehyde were heated to 170 to 180 C., 1.2 ccs. and0.6 cc. of piperidine were added at quarter-hour intervals, heating wascontinued for a further one and a quarter hours, the product cooled,triturated with glacial acetic acid and filtered. The residue wascrystallised from glacial acetic acid asyellow needles, melting point290 C.

2-am'in o"-4':4"-dicyanostilbene 10.0 gramsof:2snitroir4=dicyanostilbene thus prepared were suspendediin, Z'GOJccs;ofEfglac-ia'l acetic'acid and a'hot solution of 50 gramso'fistannouschloride (SnClzLZI-BO) in 50 cos. of. comm. tratedhydrochloricuacid' was quickly; addeds:

Rapid reaction occurred and the boiling was continued for a further 4minutes, the reaction mixture was cooled, filtered, and the stannouschloride residue decomposed with 25% aqueous caustic soda solution. Theliberated amine crystallised from glacial acetic acid as yellow needles,melting point 232 C.

2-hydroxy-4:4'-dicyanostilbene 10 grams of 2-amino-4:4'-dicyanostilbenethus prepared were dissolved in 400 ccs. of boiling glacial acetic acidand 200 cos. of dilute sulphuric acid added; the solution was suddenlychilled and diazotised over one and a half hours at to C. with sodiumnitrite (3.0 grams/l5 ccs. H2O). The diazonium salt solution was decom--posed by boiling for minutes with 600 cos. of 55% aqueous sulphuric acidsolution; the solution was diluted, cooled and filtered. The residuecrystallised from ethyl alcohol as lemon yellow prismatic needles,melting point 296 C.

2-hydroacy-4 :4 -diamidino -stilb ene 10 grams of2-hydroxy-l:4'-dicyanostilbene were suspended in 250 ccs. of absoluteethyl. alcohol and the mixture saturated with dry-hydrogen chloride at 0C. The whole was left for eight days at room temperature. Theimino-ether hydrochloride formed was filtered ofi, washed with dryether, and dried in the air for a short time. It was then added to cccs. of 10% ethyl alcoholic ammonia and the whole heated for five hoursat C. The 2-hydroxy-4:4-diamidinostilbene dihydrochloride whichseparated was crystallised from 10% hydrochloric acid. It forms paleyellow needles, melting point 357 C. (Decomp).

2hydroxy-4:4'-diamidino-stilbene was obtained from its dihydrochlorideby basification with dilute sodium carbonate. On crystallisation fromnitrobenzene, the base separates in the form 3 of micro yellow crystalshaving a melting point of 235 C. (Decomp).

Other salts (than the dihydrochloride) of the compound of the inventionmay be obtained from the dihydrochloride, for example, by the additionof dilute alkali, dissolving the base thus produced in a solution of theappropriate acid (corresponding to the desired salt) and isolating theresulting salt. Thus, for example, the di-isethionate may be produced bytreating a solution of the dihydrochloride with alkali carbonate,separating and dissolving the resultant base in aqueous isethionic acidand precipitating the di-isethionate with acetone. The product may bepurified by dissolving in hot methyl alcohol containing a trace of waterfollowed by precipitation by the cautious addition of acetone. Thedi-isethionate has a melting point of 286 0. Alternatively, the saidsalts (as also the dihydrochloride) may be prepared by reacting thecorresponding ammonium salt with 2-hydroxy-stilbene-l 4'-bis-(carboniminoethyl ether) in aqueous alcoholic solution or suspension.Representative examples of such salts, in addition to thedihydrochloride and diisethionate mentioned above, are thedi-fl-hydroxy-propane sulphonate, the di-lactate and the di-methanesulphonate.

The superiority of the compound of this inven tion over theunsubstituted compound, 4:4=-diamidino-stilbene is shown in thefollowing table giving the respective chemotherapeutic ratios of thecompounds, as determined experimentally by their effect on infections ofTr. equiperdum in mice. It will be seen that the product of the in- 4vention has a chemotherapeutic ratio at least three times as great asthat of 4:4-dlamidinostilbene.

5 Table 4:4-Diarnidino- 2-Hydr0xy-4:4-distilbene amidinostilbene I S I Sf) 0. 03 O. 125 0. 027 0. l4 0. 01 0. 01 0. 0035 0. 0035 3 12v 5 approx.8 40 I=by intravenous injection. 15 S=by subcutaneous injection.

L. D.5o=dosage which kills 50% of uninfected mice. 0. D.5u=dosage whichcures 50% olflinected mice.

. .50 Chemotherapeutic ratio (0. R.) Q D I claim: 9 2-hydroxy-44'-diamidino-stilbene.

ARTHUR JAMES EW'INS.

REFERENCES CITED The following references are of record in the file ofthis patent:

FOREIGN PATENTS Country Date Australia Mar. 25, 1943 OTHER REFERENCESNumber

